Preparation method of high-capacity carbon-silicon composite negative material

The invention discloses a preparation method of a high-capacity carbon-silicon composite negative material. The method comprises the following steps: firstly crushing leftover wastes of photovoltaic monocrystalline silicon wafers via a crushing machine, finely grinding the leftover wastes via a sand grinder, sieving, removing impurities by using an acid solution, then ball milling the obtained monocrystalline silicon powder and a graphite material in a solvent to obtain precursor powder, adding the precursor powder into an asphalt organic solution, uniformly dispersing, drying after the solvent is completely volatilized, and pre-sintering and calcining to obtain the high-capacity carbon-silicon composite negative material. Through the preparation method of the high-capacity carbon-silicon composite negative material, the leftover wastes of the photovoltaic monocrystalline silicon wafers are used as silicon sources, a layer of carbon material is coated on the surface of the monocrystalline silicon/ graphite precursor powder, and a buffering layer is provided for volume expansion of silicon, so that conductivity and cycle stability of the material are improved; by adopting the preparation disclosed by the invention, the waste resources are reused; the preparation method is simple and environmentally friendly, and is low in cost; the prepared high-capacity carbon-silicon composite negative material has excellent cycle performance and high rate capability, can meet the usage requirements on lithium-ion energy storage and power batteries, and has a good application prospect.